1. A particularly large crap.
2. The release of diaria often before a sporting activity of some importance.
3. The gathering of teamates to release excess waste before a sporting activity.
This term originated when the Cardinal Gibbons varsity lacrosse team joined in the act of crapping before a game vs Durham Academy. The legacy and tradition of the pregame still lives on to this day.

John: "Yo Kev!"
Kev: "What you want?"
John: "You ready for the big game?"
Kev: "Yeah, im stretched and ready to go- theres only one thing left to be done."
"PREGAME!"
"PREGAME!" they chanted together
"PREGAME!"
"PREGAME!"
"PREGAME!"
"PREGAME!"
"PREGAME!"
"PREGAME!"
"PREGAME!"
"PREGAME!"
"PREGAME!"
"PREGAME!!!!!!! AAAAAHHHHH"
and they proceeded to release their waste in the ceremonious bonding ritual of the pregame.

n. To drink before going to a party. This most often happens because they party where you are going to will be carding and you are under or because you want to drink something hard to start your night off. Often pregaming happens at the house and involves taking shots.
v. The act of partaking in a pregame.

1) We really need to pregame tonight before we go out.
2) I really pregamed heavily last night. I feel really sick now.

Verb. To drink. Derived originally from tailgating before a sporting event such as a football game, it later became known as drinking before any gathering. It now refers simply to drinking, because any activity afterward is acceptable to drink for.

You: Dude, let's go out and shoot some pool.
Me: Naw I'm just gonna pregame and play some Nintendo, then go to bed.
You: What you pregaming for?
Me: Bed.